Mohs hardness scale and observations on hardness of some additional materials

▪ Table

Mohs hardness scale and observations on hardness of some additional materials

mineral Mohs hardness other materials observations on the minerals

talc   1 very easily scratched by the fingernail; has a greasy feel

gypsum   2 Mohs hardness scale and observations on hardness of some additional materials2.2 fingernail can be scratched by the fingernail

calcite   3 Mohs hardness scale and observations on hardness of some additional materials3.2 copper penny very easily scratched with a knife and just scratched with a copper coin

fluorite   4 very easily scratched with a knife but not as easily as calcite

apatite   5 Mohs hardness scale and observations on hardness of some additional materials5.1 pocketknife scratched with a knife with difficulty

Mohs hardness scale and observations on hardness of some additional materials5.5 glass plate

orthoclase   6 Mohs hardness scale and observations on hardness of some additional materials6.5 steel needle cannot be scratched with a knife, but scratches glass with difficulty

quartz   7 Mohs hardness scale and observations on hardness of some additional materials7.0 streak plate scratches glass easily

topaz   8 scratches glass very easily

corundum   9 cuts glass

diamond 10 used as a glass cutter

Source: Modified from C. Klein, Minerals and Rocks: Exercises in Crystallography, Mineralogy, and Hand Specimen Petrology. Copyright 1989 John Wiley & Sons. Reprinted by permission of John Wiley & Sons, Inc.

See as table:

* * *